EP0658431A2 - Measuring apparatus for the ink-level in ink-jet printing unit - Google Patents
Measuring apparatus for the ink-level in ink-jet printing unit Download PDFInfo
- Publication number
- EP0658431A2 EP0658431A2 EP94309304A EP94309304A EP0658431A2 EP 0658431 A2 EP0658431 A2 EP 0658431A2 EP 94309304 A EP94309304 A EP 94309304A EP 94309304 A EP94309304 A EP 94309304A EP 0658431 A2 EP0658431 A2 EP 0658431A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- ink
- reservoir
- electrodes
- level
- volume
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
- B41J2/17566—Ink level or ink residue control
Definitions
- the present invention relates to a measuring apparatus for the ink-level in ink-jet printing unit and more particularly to a measuring apparatus for the ink-level in an ink-jet thermal printing unit comprising an ink-jet thermal printing head integral with the reservoir which is repeatedly rechargeable, whenever the ink has dropped to a pre-determined volume.
- the recharging may be carried out by means of a syringe, or by means of a small capacity cartridge compared with that of the reservoir, as described in European patent application N° 943006684.5 in the name of the applicant.
- End of ink detection apparatus are known in the state of the art for printing units and more generally for units with an ink-jet printing head.
- US patent N° 4 183 029 describes a detection apparatus showing the end of ink flow in the duct between the reservoir and the printing-head, due to an obstruction therein, caused by an air bubble or an impurity.
- US patent N° 5 051 759 describes an ink-end detector, in which two electrodes are fitted in the sponge located in the reservoir and impregnated with ink. The electrodes are connected to a detector circuit that measures the electrical resistance of the ink placed between the electrodes. As known, as the ink is consumed, the sponge progressively empties from one end to the other where the electrodes are fitted. However the ink resistance does not vary extensively until the level of the ink reaches the zone of the electrodes, then rapidly increases thereafter.
- US patent N° 5 136 305 describes a similar end of ink detector, whereby a thermistor is inserted into the sponge, in contact with the ink and receiving a d.c. supply. Measurement of the temperature increase of the thermistor represents the reduction in volume of ink in the sponge.
- US patent N° 5 162 817 describes an end of ink detector for an ink-jet printing head fed by a replaceable cartridge.
- the head comprises its own reservoir complete with an ink-impregnated sponge, onto which the cartridge can be coupled.
- the detector comprises three electrodes fitted in the sponge and selected in pairs for detection with the head in the horizontal or the vertical position.
- European patent application N° 440 110 describes another end of ink detector for an ink-jet printer wherein the reservoir containing an ink-impregnated sponge can be replaced and connected to the head by means of a hollow needle penetrating the reservoir.
- the reservoir has two electrodes, one fitted in the sponge, and the other inserted in the feed duct to the head.
- the detection circuit comprises a compensation resistance for the ink-viscosity according to the temperature.
- Such apparatus are nevertheless not able to indicate continuous variations in the quantity of ink contained in the reservoir in an intermediate zone between minimum and maximum ink content.
- Preferred embodiments of the present invention thus may comprise means to measure the ink-level in a rechargeable unit, able to signal at least one of the extremes, preferably the lower end of an ink-volume variation range, comprised between the minimum remaining volume and the maximum available volume in the reservoir, thus allowing with sufficient precision to determine the moment when the reservoir needs refill with a predetermined volume of ink.
- Fig. 2 represents, as a non-restrictive application example of the invention, a rechargeable printing unit 10 of the type described in the European patent application N° 94306684.5 in the name of the Applicant, which consists of a main structure 11, comprising a reservoir 12 for the ink and an auxiliary structure 16 integral with the main structure 11 and comprising an aperture 18 to admit the refill cartridge 20, inserted in the aperture 18 when the ink in the reservoir 12 has reached a predetermined minimum level.
- the reservoir 12 is defined at the bottom by a wall 14 on the outer face 22 of which an ink-jet thermal printing head 24 is mounted.
- the print-head consists of an integrated circuit technique silicon chip, including a plurality of nozzles 25, the relevant emission chambers and relevant emission resistors, not visible in the figure.
- a feed chamber 28 is located closed at the top by a diaphragm 30 permeable to the ink, but not to air, and communicating with the print-head 24 through a duct 31 passing through a bottom wall 14.
- the reservoir 12 is filled with absorbent material 34 such as for instance a fibre or felt agglomerate, or a pack of layers of non woven textile (TNT), which is impregnated with ink at the time of assembly of the unit.
- absorbent material 34 such as for instance a fibre or felt agglomerate, or a pack of layers of non woven textile (TNT), which is impregnated with ink at the time of assembly of the unit.
- the reservoir 12 After filling with ink, the reservoir 12 is closed in a stable manner with a cover 35 having an aperture 37 to vent the reservoir 12 to atmospheric pressure.
- the absorbent material 34 consists of a pack of sheets or layers of non-woven textile, a material known in the state of the art, and sold under various names according to the nature of the base material, as for instance:
- These materials consist of one or several layers of synthetic fibre placed at random one on top of the other, and bonded together at contact points, so as to form a flat structure like a sheet.
- the sheets cut to the required dimensions are stacked in clearly defined numbers, so as to form a pack which is then inserted into the reservoir 12; as an alterative the pack may be obtained by folding like an accordion a sheet of the material of the required height.
- the number of layers forming the pack must be accurately defined, since any variation of that number (for a same thickness of sheet) produces a greater or lesser level of fibre compression and of consequent control over the resultant capillarity.
- a layer of slightly compressed spongy material 36 is inserted, intended to ensure the flow of ink towards the chamber 28, through the diaphragm 30, by its capillarity.
- the duration of the ink is notably shorter than the life of the print-head 24.
- the printing unit 10 is arranged so as to admit a refill cartridge 20, easily inserted to recharge the reservoir 12 with new ink, and easily removable when the refilling is completed.
- two metal plates 40, 41 are placed in the reservoir 12 (Figs. 3 & 4) against respectively opposing walls 43, 44 and including between them the pack 34 of fibrous material.
- the size of plates 40, 41 is such as to cover completely the end faces of the pack 34 (Fig. 4) and serve as electrodes in contact with the ink to detect the level of ink contained in the reservoir 12, as will be explained further on, and may be made of stainless steel or gold-plated copper, or any other electrically conductive material which withstands chemical attack by the ink.
- the electrodes 40, 41 may also be designed as a sufficiently close-meshed grid, or netting or mesh of one of the previously defined materials.
- a block (Fig. 4) is firstly prepared, consisting of pack 34 included between the electrodes 40, 41, cut to measure in such a manner as to allow its easy single-operation insertion into the reservoir.
- Each of the electrodes 40, 41 has a fin 46 projecting outside the reservoir 12 (Fig. 3) forming an electrical terminal for connection to a detection circuit (Fig. 6) described further on.
- Fig. 5 shows a different embodiment of the electrodes 40,41, designed in the form of a flexible film (flat cable) 48 on which two metal zones 50, 51 are deposited each connected to an electrical terminal 46 and extending in such a manner as to be superimposed completely over the end faces of the fibre pack 34.
- the film 48 may consist for instance of MYLAR (Registered trademark) or some other material having the same properties.
- the film 48 is folded at right angles to match lines 55 & 56 then wound onto pack 34 so as to fully superimpose the metal zones 50, 51 on opposing faces of the pack 34.
- the distance between lines 55, 56 obviously coincides with the thickness H (Fig. 4) of the pack 34.
- the group consisting of the pack 34 and film 48 is then inserted into the reservoir 12.
- the electrodes 40, 41 may be produced by silk-screen printing technique featuring a layer of electrically conductive and chemically inert material deposited on the inner face of two opposing walls 43, 44 of the reservoir 12.
- the electrical resistance R k of the ink being such as to cover the whole of the volume of ink contained in the pack 34 and fully interposed between electrodes 40, 41.
- the resistance R k varies in inverse proportion with the volume (or with the ink level, assuming an equal section) according to a sufficiently accurate law for up to about 80% of the ink contained in the reservoir 12.
- the abscissae S% represent the % consumption of the total ink in the reservoir.
- ink resistance variations show no significant hysteresis, and measurement of the ink level can be repeated several times with good accuracy.
- a small size printing unit i.e. capable of containing 5-6 cm3 of ink and rechargeable by way of a cartridge, as shown in Fig. 2, to ensure a degree of repetitive and constant filling, it has been found that refilling with new ink can be suitably effected when the ink consumption S% has reached approximately 2/3 (66%) of the available ink in the reservoir 12 (Fig.7), or in other words when a minimum quantity of 25% to 40% of ink remains in the reservoir and preferably of the order of 33% of the maximum admissible volume.
- the volume of ink which can be added in an optimum manner i.e. in the shortest possible time and uniformly impregnating the absorbent material 34, is of the order of 1/3 of the total, viz. approximately 2 cm3.
- Two resistances Rs and Rt in series form a resistive voltage divider connected between the supply voltage V and earth M.
- An intermediate point P between the two resistors is connected to a first input 61 of a switch 60.
- a second input 62 of the switch 60 is connected at a point A to one of the two electrodes, for instance to electrode 40.
- the other electrode 41 is connected to earth M through a transistor T, which connects electrode 41 to earth for brief moments only, in response to a signal S, to avoid any ink electrolysis phenomenon.
- the first electrode 40 is also connected at point A to a resistor Re in turn connected to the voltage supply V.
- Resistor Re functions as a balancing and compensation resistance for several resistance values of differing inks, as may be seen further on.
- the switch 60 is connected to an analog/digital converter (A/D) 64 which in turn is connected by a bus 66 to a microprocessor 68.
- A/D analog/digital converter
- the switch 60 is preferably integrated, together with the A/D converter 64 and the microprocessor 68, in a single integrated circuit chip 70.
- the microprocessor 68 processes the voltage values recorded at points P and A each time the transistor T is activated by the signal S from the microprocessor 68.
- the apparatus according to the invention is preset to allow for the said variations and compensate them as described further on.
- the resistivity variation versus the temperature is mainly caused by the differing ionic mobility of the ink base solution, as represented by a typical temperature coefficient "ct", which, as an example, may be: 0.013 in the temperature range between 10 and 60°C.
- the resistor Rt is therefore preferably a thermistor having the same temperature coefficient "ct" as the ink, so that the voltage at point P (threshold value) also varies with the temperature.
- the resistor Rt is compensated after assigning a specific value to the resistance Re.
- the resistivity of a given type of ink measured between electrodes 40, 41 is 100 ohms when the reservoir is full, whilst after consumption of approximately 2/3 of the total, that resistivity has increased to 500 ohms.
- a resistor Re with a value of 500 ohms, is then selected for that type of ink, so that, when the ink level has dropped to the value shown above, the voltage at point A being V/2.
- the resistor Re may have, of course, other values allocated to it, without limiting the scope of the present invention.
- the resistor Re may be directly integrated in the print-head 24 silicon chip, as well as emission resistors R1, R2,...Ri (Fig. 6). In that case, since a terminal C of resistor Re is connected to the supply V, the common supply track D, already present in the print-head 24 silicon chip, can save an external connection.
- the microprocessor 68 records the voltage value at point A and, after triggering switching of the switch 60, proceeds with a comparison with the voltage at point P, already temperature-compensated by resistance Rt. As soon as the voltage at point A reaches the anticipated value V/2, the microprocessor generates a signal non-specifically shown here, to activate an alarm apparatus in a known manner, to indicate to the operator that the ink supply must be refilled.
- the resistor Rt may be a normal temperature sensor disassociated from the particular value of the ink temperature coefficient "ct" and fixed to the printing unit 10 as nearest as possible to the print-head 24.
- the microprocessor 68 records the temperature of the ink and, using a conversion table stored in part of the memory M of the microprocessor 68, calculates an equivalent threshold voltage, to which the voltage at point A is compared.
Abstract
Description
- The present invention relates to a measuring apparatus for the ink-level in ink-jet printing unit and more particularly to a measuring apparatus for the ink-level in an ink-jet thermal printing unit comprising an ink-jet thermal printing head integral with the reservoir which is repeatedly rechargeable, whenever the ink has dropped to a pre-determined volume. The recharging may be carried out by means of a syringe, or by means of a small capacity cartridge compared with that of the reservoir, as described in European patent application N° 943006684.5 in the name of the applicant.
- End of ink detection apparatus are known in the state of the art for printing units and more generally for units with an ink-jet printing head.
- In particular US patent N° 4 183 029 describes a detection apparatus showing the end of ink flow in the duct between the reservoir and the printing-head, due to an obstruction therein, caused by an air bubble or an impurity.
- US patent N° 5 051 759 describes an ink-end detector, in which two electrodes are fitted in the sponge located in the reservoir and impregnated with ink. The electrodes are connected to a detector circuit that measures the electrical resistance of the ink placed between the electrodes. As known, as the ink is consumed, the sponge progressively empties from one end to the other where the electrodes are fitted. However the ink resistance does not vary extensively until the level of the ink reaches the zone of the electrodes, then rapidly increases thereafter.
- US patent N° 5 136 305 describes a similar end of ink detector, whereby a thermistor is inserted into the sponge, in contact with the ink and receiving a d.c. supply. Measurement of the temperature increase of the thermistor represents the reduction in volume of ink in the sponge.
- US patent N° 5 162 817 describes an end of ink detector for an ink-jet printing head fed by a replaceable cartridge. The head comprises its own reservoir complete with an ink-impregnated sponge, onto which the cartridge can be coupled. The detector comprises three electrodes fitted in the sponge and selected in pairs for detection with the head in the horizontal or the vertical position.
- European patent application N° 440 110 describes another end of ink detector for an ink-jet printer wherein the reservoir containing an ink-impregnated sponge can be replaced and connected to the head by means of a hollow needle penetrating the reservoir. The reservoir has two electrodes, one fitted in the sponge, and the other inserted in the feed duct to the head. The detection circuit comprises a compensation resistance for the ink-viscosity according to the temperature.
- All of the end of ink detector apparatus outlined above have one similar characteristic in common. i.e. that the ink reservoir contains a sponge, with the electrodes fitted therein close to the ink outlet hole. For that reason the end of ink signal obtained as a function of the variation in resistance of the ink between electrodes, is only generated when a small volume of ink remains in the reservoir, representing approximately 15% of the total, corresponding to a consumption of approximately 85% of the total available volume. This is due to the fact that the curve (Fig. 1) for ink resistance Rk variation between electrodes, as a function of the ink consumption S% is essentially flat until the ink-consumption S% reaches approximately 85% of the total, as previously stated, before suddenly rising beyond that value.
- Such apparatus are nevertheless not able to indicate continuous variations in the quantity of ink contained in the reservoir in an intermediate zone between minimum and maximum ink content.
- Preferred embodiments of the present invention thus may comprise means to measure the ink-level in a rechargeable unit, able to signal at least one of the extremes, preferably the lower end of an ink-volume variation range, comprised between the minimum remaining volume and the maximum available volume in the reservoir, thus allowing with sufficient precision to determine the moment when the reservoir needs refill with a predetermined volume of ink.
- This may be achieved by the measuring apparatus of the invention, characterised in the manner defined in the main claim.
- That and other characteristics of the invention will be more clearly discerned from the following description of a preferred embodiment, given for the purposes of a non-restrictive example, and referring to the appended drawings.
-
- Fig. 1 represents a typical resistance variation curve for the ink between two electrodes, as knowing in the present art;
- Fig. 2 represents an ink-jet printing unit adapted for mounting a measuring apparatus embodying the invention;
- Fig. 3 represents a section along III-III in Fig. 2;
- Fig. 4 represents a fibre pack located between two electrodes and contained within the unit in Fig. 2;
- Fig. 5 represents a second embodiment of the electrodes in Fig. 4;
- Fig. 6 represents an electrical circuit for measuring the ink level in an embodiment of the invention;
- Fig. 7 represents a resistance variation curve for the ink between two electrodes, obtained by means of the apparatus embodying the invention.
- Fig. 2 represents, as a non-restrictive application example of the invention, a
rechargeable printing unit 10 of the type described in the European patent application N° 94306684.5 in the name of the Applicant, which consists of amain structure 11, comprising areservoir 12 for the ink and anauxiliary structure 16 integral with themain structure 11 and comprising anaperture 18 to admit therefill cartridge 20, inserted in theaperture 18 when the ink in thereservoir 12 has reached a predetermined minimum level. - The
reservoir 12 is defined at the bottom by awall 14 on theouter face 22 of which an ink-jetthermal printing head 24 is mounted. The print-head consists of an integrated circuit technique silicon chip, including a plurality ofnozzles 25, the relevant emission chambers and relevant emission resistors, not visible in the figure. - On the inside of the reservoir 12 a
feed chamber 28 is located closed at the top by adiaphragm 30 permeable to the ink, but not to air, and communicating with the print-head 24 through aduct 31 passing through abottom wall 14. - The
reservoir 12 is filled withabsorbent material 34 such as for instance a fibre or felt agglomerate, or a pack of layers of non woven textile (TNT), which is impregnated with ink at the time of assembly of the unit. - After filling with ink, the
reservoir 12 is closed in a stable manner with a cover 35 having anaperture 37 to vent thereservoir 12 to atmospheric pressure. - During the filling of the
reservoir 12, particular care is taken to ensure that the ink completely fills thechamber 28, theduct 31 and the emission chambers of the print-head 24, so as to ensure its satisfactory operation. - According to a preferred non-restrictive form of design of the
printing unit 10, theabsorbent material 34 consists of a pack of sheets or layers of non-woven textile, a material known in the state of the art, and sold under various names according to the nature of the base material, as for instance: - Reemay (Reemay Inc registered trademark) :polyester
- Tekton (Reemay Inc registered trademark) :polypropylene
- Sontara (Du Pont registered trademark) :polyester
- Nordlys (Nordlys Inc registered trademark) :polyamide
- These materials consist of one or several layers of synthetic fibre placed at random one on top of the other, and bonded together at contact points, so as to form a flat structure like a sheet.
- The sheets cut to the required dimensions are stacked in clearly defined numbers, so as to form a pack which is then inserted into the
reservoir 12; as an alterative the pack may be obtained by folding like an accordion a sheet of the material of the required height. - In each case, the number of layers forming the pack must be accurately defined, since any variation of that number (for a same thickness of sheet) produces a greater or lesser level of fibre compression and of consequent control over the resultant capillarity.
- Between the
pack 34 of non-woven sheet and the diaphragm 30 a layer of slightly compressedspongy material 36 is inserted, intended to ensure the flow of ink towards thechamber 28, through thediaphragm 30, by its capillarity. - In the case of a small
size printing unit 10 for instance suitable to be inserted in a portable or low-end ink-jet printer, able to contain approximately 5-6 cm³ of ink, the duration of the ink is notably shorter than the life of the print-head 24. - Thus in order to avoid throwing away the empty unit with a still
efficient head 24, theprinting unit 10 is arranged so as to admit arefill cartridge 20, easily inserted to recharge thereservoir 12 with new ink, and easily removable when the refilling is completed. - It is consequently necessary to know with sufficient accuracy the minimum remaining ink level in the
reservoir 12 of theunit 10, following which the refill cartridge has to be inserted into theaperture 18 to provide a new ink supply. - According to tests carried out by the inventor, it has proved useful to refill the
unit 10 when the remaining volume of ink in thereservoir 12 has dropped to approximately one third of the total capacity of thereservoir 12. - For that purpose two
metal plates walls pack 34 of fibrous material. The size ofplates reservoir 12, as will be explained further on, and may be made of stainless steel or gold-plated copper, or any other electrically conductive material which withstands chemical attack by the ink. Theelectrodes - To facilitate insertion of the
pack 34 and plates orelectrodes 40 & 41 in thereservoir 12, a block (Fig. 4) is firstly prepared, consisting ofpack 34 included between theelectrodes - Each of the
electrodes fin 46 projecting outside the reservoir 12 (Fig. 3) forming an electrical terminal for connection to a detection circuit (Fig. 6) described further on. - Fig. 5 shows a different embodiment of the
electrodes metal zones electrical terminal 46 and extending in such a manner as to be superimposed completely over the end faces of thefibre pack 34. Thefilm 48 may consist for instance of MYLAR (Registered trademark) or some other material having the same properties. Thefilm 48 is folded at right angles to match lines 55 & 56 then wound ontopack 34 so as to fully superimpose themetal zones pack 34. The distance between lines 55, 56 obviously coincides with the thickness H (Fig. 4) of thepack 34. The group consisting of thepack 34 andfilm 48 is then inserted into thereservoir 12. - As an alternative, the
electrodes walls reservoir 12. - In that way it is possible to measure by volumetric method the electrical resistance Rk of the ink, the extension of the electrodes being such as to cover the whole of the volume of ink contained in the
pack 34 and fully interposed betweenelectrodes reservoir 12. In Fig. 7 the abscissae S% represent the % consumption of the total ink in the reservoir. - Furthermore the ink resistance variations show no significant hysteresis, and measurement of the ink level can be repeated several times with good accuracy.
- In a small size printing unit, i.e. capable of containing 5-6 cm³ of ink and rechargeable by way of a cartridge, as shown in Fig. 2, to ensure a degree of repetitive and constant filling, it has been found that refilling with new ink can be suitably effected when the ink consumption S% has reached approximately 2/3 (66%) of the available ink in the reservoir 12 (Fig.7), or in other words when a minimum quantity of 25% to 40% of ink remains in the reservoir and preferably of the order of 33% of the maximum admissible volume.
- In that event the volume of ink which can be added in an optimum manner, i.e. in the shortest possible time and uniformly impregnating the
absorbent material 34, is of the order of 1/3 of the total, viz. approximately 2 cm³. - As already stated previously, it is extremely difficult with the known means to detect the ink-end with the required accuracy, when the ink reaches a level of 33% in the
reservoir 12. The measurement of the ink level in thereservoir 12 is thus effected according to the embodiment of the invention, by means of the circuit in Fig. 6 associated with theelectrodes - Two resistances Rs and Rt in series form a resistive voltage divider connected between the supply voltage V and earth M. An intermediate point P between the two resistors is connected to a
first input 61 of aswitch 60. Asecond input 62 of theswitch 60 is connected at a point A to one of the two electrodes, for instance to electrode 40. Theother electrode 41 is connected to earth M through a transistor T, which connectselectrode 41 to earth for brief moments only, in response to a signal S, to avoid any ink electrolysis phenomenon. - The
first electrode 40 is also connected at point A to a resistor Re in turn connected to the voltage supply V. Resistor Re functions as a balancing and compensation resistance for several resistance values of differing inks, as may be seen further on. - The
switch 60 is connected to an analog/digital converter (A/D) 64 which in turn is connected by abus 66 to amicroprocessor 68. Theswitch 60 is preferably integrated, together with the A/D converter 64 and themicroprocessor 68, in a single integrated circuit chip 70. Themicroprocessor 68 processes the voltage values recorded at points P and A each time the transistor T is activated by the signal S from themicroprocessor 68. - It is known that temperature variations affect the resistivity of the ink and that each type of ink has its own resistivity which may vary considerably from one type of ink to another. The apparatus according to the invention is preset to allow for the said variations and compensate them as described further on. For a given type of ink the resistivity variation versus the temperature is mainly caused by the differing ionic mobility of the ink base solution, as represented by a typical temperature coefficient "ct", which, as an example, may be: 0.013 in the temperature range between 10 and 60°C.
- To compensate such ink resistivity variations with temperature, the resistor Rt is therefore preferably a thermistor having the same temperature coefficient "ct" as the ink, so that the voltage at point P (threshold value) also varies with the temperature. However when a different type of ink is to be used, for instance of differing composition or having other chromatic characteristics, and thereby a different resistivity, the latter is compensated after assigning a specific value to the resistance Re.
- As a non-restrictive example, the resistivity of a given type of ink measured between
electrodes - The resistor Re may have, of course, other values allocated to it, without limiting the scope of the present invention.
- To simplify the design of the apparatus according to the invention, the resistor Re may be directly integrated in the print-
head 24 silicon chip, as well as emission resistors R1, R2,...Ri (Fig. 6). In that case, since a terminal C of resistor Re is connected to the supply V, the common supply track D, already present in the print-head 24 silicon chip, can save an external connection. - During operation, each time the transistor T is activated, the
microprocessor 68 records the voltage value at point A and, after triggering switching of theswitch 60, proceeds with a comparison with the voltage at point P, already temperature-compensated by resistance Rt. As soon as the voltage at point A reaches the anticipated value V/2, the microprocessor generates a signal non-specifically shown here, to activate an alarm apparatus in a known manner, to indicate to the operator that the ink supply must be refilled. - As an alternative, the resistor Rt may be a normal temperature sensor disassociated from the particular value of the ink temperature coefficient "ct" and fixed to the
printing unit 10 as nearest as possible to the print-head 24. In this event, themicroprocessor 68 records the temperature of the ink and, using a conversion table stored in part of the memory M of themicroprocessor 68, calculates an equivalent threshold voltage, to which the voltage at point A is compared. - It should of course be understood that variations, modifications or replacement of parts may be made in connection with the present apparatus to measure the ink-level in an ink-jet printing unit, without in any way diverting from the scope of the invention as defined by the appended claims.
Claims (15)
- Apparatus for measuring the ink-level in an ink-jet printing unit, comprising a print-head (24), a reservoir (12) containing a volume of ink and integral with the print-head, and means for measuring the ink level in the reservoir characterised in that, said measuring means comprise a pair of electrodes (40,41) located inside the reservoir, electrically separate and at a distance from each other so that between them they substantially contain the volume of ink.
- Apparatus according to claim 1, characterised in that, the reservoir is filled with a pack of fibrous material (34) impregnated with the ink and comprising a plurality of sheets or layers of non-woven textile, packed to a predetermined thickness.
- Apparatus according to claim 1, or 2 characterised in that, the electrodes (41,42) are separated by the thickness of the pack and are connected to a circuit measuring the level of the ink in the reservoir.
- Apparatus according to any preceding claims, characterised in that, each of the electrodes is made of a material which is electrically conductive and chemically inert with reference to the ink.
- Apparatus according to claim 4, characterised in that, each of the electrodes comprises a flat plate secured to a respective wall (43,44) of the reservoir.
- Apparatus according to claim 4, characterised in that, each of the electrodes comprises a metal mesh component.
- Apparatus according to claim 4, characterised in that, each of the electrodes comprises a thin layer of an electrically conductive and chemically inert material with reference to the ink, deposited by a silk-screen printing technique onto one internal surface of two opposing walls of the said reservoir.
- Apparatus according to claim 4, characterised in that, the electrodes comprise a layer of an electrically conductive material deposited on a thin film (48) of insulating and inert material wound around the pack of layers.
- Apparatus for measuring the ink-level in an ink-jet printing unit (10), the unit comprising a reservoir (12) containing a volume of renewable ink and having a typical resistivity, a print-head (24) comprising a plurality of resistors (Ri), and means (40,41) to measure the level of ink in the reservoir and, connected to a circuit for measuring said level, characterised in that, said means comprise a pair of electrodes (40,41) arranged in the reservoir, said print-head comprising at least one further resistor (Re) connected to the circuit and to one of the electrodes, to define in association with the resistivity at least one extreme on a variation range of the ink level, comprised between a remaining minimum volume and a maximum volume of ink contained in the reservoir between the electrodes.
- Apparatus according to claim 9, characterised in that, the further resistor (Re) is connected to at least one resistor of said plurality of resistors (Ri) and to the circuit.
- Apparatus according to claim 9, characterised in that, the further resistor is outside the print-head (24) and is part of that circuit.
- Apparatus according to any one of claims 9 to 11, characterised in that, the electrodes are separated in such a way as to contain between them the volume of ink.
- Apparatus according to any one of claims 9 to 12, characterised in that, the reservoir is filled with a pack of fibrous material (34) impregnated with the ink, the fibrous material comprising a plurality of sheets or layers of non-woven textile packed to a predetermined thickness.
- Apparatus according to claim 13, characterised in that, the electrodes are separated from each other by an amount equal to said thickness and have a surface substantially covering the end faces of the pack.
- Apparatus according to any one of claims 9 to 14, characterised in that, the remaining minimum volume is comprised between 25% and 40% of the maximum volume of ink contained in the reservoir.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITTO930953 | 1993-12-16 | ||
ITTO930953A IT1272076B (en) | 1993-12-16 | 1993-12-16 | INK LEVEL MEASURING DEVICE OF A PRINTING MODULE INK JET |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0658431A2 true EP0658431A2 (en) | 1995-06-21 |
EP0658431A3 EP0658431A3 (en) | 1996-06-26 |
EP0658431B1 EP0658431B1 (en) | 2000-05-17 |
Family
ID=11411935
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94309304A Expired - Lifetime EP0658431B1 (en) | 1993-12-16 | 1994-12-13 | Measuring apparatus for the ink-level in ink-jet printing unit |
Country Status (5)
Country | Link |
---|---|
US (1) | US5623291A (en) |
EP (1) | EP0658431B1 (en) |
JP (1) | JP3513239B2 (en) |
DE (1) | DE69424513T2 (en) |
IT (1) | IT1272076B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2765330A1 (en) * | 1997-06-27 | 1998-12-31 | Canon Kk | Method for determining the ink quantity in a reservoir of multi-reservoir ink container, for ink jet printers. |
EP0940259A3 (en) * | 1998-03-04 | 1999-11-17 | Hewlett-Packard Company | Electrical refurbishment for ink delivery system |
US6137512A (en) * | 1994-07-06 | 2000-10-24 | Canon Kabushiki Kaisha | Ink container |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3039358B2 (en) * | 1996-02-21 | 2000-05-08 | 富士ゼロックス株式会社 | Ink supply device and recording device |
US6106087A (en) * | 1996-10-01 | 2000-08-22 | Brother Kogyo Kabushiki Kaisha | Detection apparatus for detecting residual ink quantity in ink cartridge |
US6095643A (en) * | 1998-05-07 | 2000-08-01 | Lexmark International, Inc. | Refillable disposable inkjet cartridge with foam-filled and free ink reservoirs |
JP3450798B2 (en) * | 1999-04-27 | 2003-09-29 | キヤノン株式会社 | Liquid supply system, liquid storage container used in the system, and ink jet head cartridge using the system |
JP2001001544A (en) * | 1999-06-24 | 2001-01-09 | Canon Inc | Liquid supply method, liquid supply container, negative pressure generating member storing container, and liquid storing container |
US6431670B1 (en) * | 2000-02-14 | 2002-08-13 | Hewlett-Packard Company | Ink level sensing method and apparatus |
EP1990201B1 (en) * | 2000-06-16 | 2010-05-19 | Canon Kabushiki Kaisha | Communication system with solid semiconductor element, ink tank, ink jet recording apparatus provided with ink tank. |
US6412894B1 (en) | 2001-01-19 | 2002-07-02 | Lexmark International, Inc. | Ink cartridge and method for determining ink volume in said ink cartridge |
DE60231449D1 (en) * | 2001-05-17 | 2009-04-23 | Seiko Epson Corp | Ink injection method for an ink cartridge |
US6663234B2 (en) * | 2001-06-11 | 2003-12-16 | Xerox Corporation | Ink cartridge providing improved ink supply |
ITTO20020428A1 (en) * | 2002-05-20 | 2003-11-20 | Tecnost Sistemi S P A | INK JET PRINTER WITH HIGH CAPACITY TANK AND RELATED INK SUPPLY SYSTEM. |
GB2390461B (en) * | 2002-07-02 | 2005-06-15 | Autoliv Dev | Improvements in or relating to a triggering unit |
US6874861B2 (en) * | 2003-04-29 | 2005-04-05 | Hewlett-Packard Development Company, L.P. | Printing device having a printing fluid detection system |
US6966222B2 (en) * | 2003-12-08 | 2005-11-22 | Hewlett-Packard Development Company, L.P. | Methods and apparatus for media level measurement |
WO2005109387A2 (en) * | 2004-05-06 | 2005-11-17 | Thomson Licensing | Pixel shift display with minimal noise |
WO2005109384A2 (en) * | 2004-05-06 | 2005-11-17 | Thomson Licensing | Pixel shift display with minimal noise |
US7322681B2 (en) * | 2005-10-11 | 2008-01-29 | Silverbrook Research Pty Ltd | Printhead with ink feed to chamber via adjacent chamber |
DE602006016874D1 (en) * | 2006-05-31 | 2010-10-21 | Telecom Italia Spa | INK JET CARTRIDGE WITH A TWO POROUS WALL-SHAPING INK TANK |
DE202012103028U1 (en) * | 2012-08-10 | 2013-11-12 | Bormann EDV + Zubehör GmbH, Versandbuchhandel und Verlag | ink cartridge |
US20140183087A1 (en) * | 2012-12-31 | 2014-07-03 | Funai Electric Co., Ltd. | Fluid Level Sensing Tank Materials |
EP3092465B1 (en) | 2014-01-09 | 2021-02-24 | Siemens Healthcare Diagnostics Inc. | Fluid containers with integrated level sensing |
WO2018067169A1 (en) | 2016-10-07 | 2018-04-12 | Hewlett-Packard Development Company, L.P. | Fluid reservoir with fluid property and level detection |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4202267A (en) * | 1976-04-23 | 1980-05-13 | Siemens Aktiengesellschaft | Device for monitoring the ink supply in ink-operated printers |
JPS5943340A (en) * | 1982-09-03 | 1984-03-10 | Nippon Telegr & Teleph Corp <Ntt> | Detection of ink viscosity |
JPS6246650A (en) * | 1985-08-27 | 1987-02-28 | Seiko Epson Corp | Ink amount detector |
US5051759A (en) * | 1989-01-13 | 1991-09-24 | Canon Kabushiki Kaisha | Ink jet cartridge and ink tank |
JPH03222755A (en) * | 1990-01-30 | 1991-10-01 | Seiko Epson Corp | Ink end detection system for ink jet recording device |
JPH04173251A (en) * | 1990-11-06 | 1992-06-19 | Ricoh Co Ltd | Ink detecting device for recorder |
JPH04182141A (en) * | 1990-11-15 | 1992-06-29 | Ricoh Co Ltd | Ink detector for recording device |
JPH04282256A (en) * | 1991-03-12 | 1992-10-07 | Seiko Epson Corp | Ink jet recording device |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2728283C2 (en) * | 1977-06-23 | 1982-04-29 | Siemens AG, 1000 Berlin und 8000 München | Device for monitoring the ink supply in ink writing devices |
JPS5820870Y2 (en) * | 1977-07-28 | 1983-05-02 | 株式会社東芝 | Dryer |
US5162817A (en) * | 1989-01-28 | 1992-11-10 | Canon Kabushiki Kaisha | Ink jet with residual ink detection that compensates for different ink properties |
US5070346A (en) * | 1990-01-30 | 1991-12-03 | Seiko Epson Corporation | Ink near-end detecting device |
US5136305A (en) * | 1990-12-06 | 1992-08-04 | Xerox Corporation | Ink jet printer with ink supply monitoring means |
IT1245065B (en) * | 1991-04-15 | 1994-09-13 | Olivetti & Co Spa | INK DETECTOR DEVICE FOR A LIQUID INK PRINTING ELEMENT |
US5289212A (en) * | 1992-05-19 | 1994-02-22 | Xerox Corporation | Air vent for an ink supply cartridge in a thermal ink-jet printer |
DE4301967A1 (en) * | 1993-01-26 | 1994-07-28 | Dynamit Nobel Ag | Cartridge made of plastic for a shooting device, in particular a bolt-setting tool |
-
1993
- 1993-12-16 IT ITTO930953A patent/IT1272076B/en active IP Right Grant
-
1994
- 1994-12-06 US US08/354,028 patent/US5623291A/en not_active Expired - Lifetime
- 1994-12-13 DE DE69424513T patent/DE69424513T2/en not_active Expired - Lifetime
- 1994-12-13 EP EP94309304A patent/EP0658431B1/en not_active Expired - Lifetime
- 1994-12-16 JP JP31357994A patent/JP3513239B2/en not_active Expired - Lifetime
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4202267A (en) * | 1976-04-23 | 1980-05-13 | Siemens Aktiengesellschaft | Device for monitoring the ink supply in ink-operated printers |
JPS5943340A (en) * | 1982-09-03 | 1984-03-10 | Nippon Telegr & Teleph Corp <Ntt> | Detection of ink viscosity |
JPS6246650A (en) * | 1985-08-27 | 1987-02-28 | Seiko Epson Corp | Ink amount detector |
US5051759A (en) * | 1989-01-13 | 1991-09-24 | Canon Kabushiki Kaisha | Ink jet cartridge and ink tank |
JPH03222755A (en) * | 1990-01-30 | 1991-10-01 | Seiko Epson Corp | Ink end detection system for ink jet recording device |
JPH04173251A (en) * | 1990-11-06 | 1992-06-19 | Ricoh Co Ltd | Ink detecting device for recorder |
JPH04182141A (en) * | 1990-11-15 | 1992-06-29 | Ricoh Co Ltd | Ink detector for recording device |
JPH04282256A (en) * | 1991-03-12 | 1992-10-07 | Seiko Epson Corp | Ink jet recording device |
Non-Patent Citations (6)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 11, no. 234 (M-611) [2681] , 30 June 1987 & JP-A-62 046650 (SEIKO), 28 February 1987, * |
PATENT ABSTRACTS OF JAPAN vol. 15, no. 505 (M-1194), 20 December 1991 & JP-A-03 222755 (SEIKO), 1 October 1991, * |
PATENT ABSTRACTS OF JAPAN vol. 16, no. 477 (M-1320), 5 October 1992 & JP-A-04 173251 (RICOH), 19 June 1992, * |
PATENT ABSTRACTS OF JAPAN vol. 16, no. 494 (M-1324), 13 October 1992 & JP-A-04 182141 (RICOH), 29 June 1992, * |
PATENT ABSTRACTS OF JAPAN vol. 17, no. 83 (M-1369), 18 February 1993 & JP-A-04 282256 (SEIKO) * |
PATENT ABSTRACTS OF JAPAN vol. 8, no. 144 (P-284), 5 July 1984 & JP-A-59 043340 (NIPPON DENSHIN), 10 March 1984, * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6137512A (en) * | 1994-07-06 | 2000-10-24 | Canon Kabushiki Kaisha | Ink container |
US6394591B1 (en) | 1994-07-06 | 2002-05-28 | Canon Kabushiki Kaisha | Ink container |
US6412932B1 (en) | 1994-07-06 | 2002-07-02 | Canon Kabushiki Kaisha | Ink container, ink jet head having ink container, ink jet apparatus having ink container, and manufacturing method for ink container |
US6578957B2 (en) | 1994-07-06 | 2003-06-17 | Canon Kabushiki Kaisha | Ink container, ink jet head having ink container, ink jet apparatus having ink container, and manufacturing method for ink container |
US6227638B1 (en) | 1997-01-21 | 2001-05-08 | Hewlett-Packard Company | Electrical refurbishment for ink delivery system |
FR2765330A1 (en) * | 1997-06-27 | 1998-12-31 | Canon Kk | Method for determining the ink quantity in a reservoir of multi-reservoir ink container, for ink jet printers. |
US6318826B1 (en) | 1997-06-27 | 2001-11-20 | Canon Kabushiki Kaisha | Device for determining a quantity of consumable product, notably ink, present in a reservoir with a number of compartments, and corresponding document printing device |
EP0940259A3 (en) * | 1998-03-04 | 1999-11-17 | Hewlett-Packard Company | Electrical refurbishment for ink delivery system |
Also Published As
Publication number | Publication date |
---|---|
JP3513239B2 (en) | 2004-03-31 |
JPH07209060A (en) | 1995-08-11 |
IT1272076B (en) | 1997-06-11 |
EP0658431B1 (en) | 2000-05-17 |
EP0658431A3 (en) | 1996-06-26 |
US5623291A (en) | 1997-04-22 |
ITTO930953A1 (en) | 1995-06-16 |
DE69424513T2 (en) | 2001-01-18 |
ITTO930953A0 (en) | 1993-12-16 |
DE69424513D1 (en) | 2000-06-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0658431B1 (en) | Measuring apparatus for the ink-level in ink-jet printing unit | |
US5289211A (en) | Ink detecting device for a liquid-ink printing element | |
US6007173A (en) | Ink status system for a liquid ink printer | |
KR910007323B1 (en) | Ink jet pen | |
EP0562733B1 (en) | An ink container for an ink jet print head | |
AU701490B2 (en) | Liquid level sensor for ink jet printers | |
US5731824A (en) | Ink level sensing system for an ink jet printer | |
US6099101A (en) | Disabling refill and reuse of an ink jet print head | |
US7370528B2 (en) | System for detecting the level of liquid in a tank | |
US6318826B1 (en) | Device for determining a quantity of consumable product, notably ink, present in a reservoir with a number of compartments, and corresponding document printing device | |
US5386224A (en) | Ink level sensing probe system for an ink jet printer | |
EP3349601A1 (en) | Cartridge with a capacity sensor | |
JP2001253088A (en) | Printer | |
JP2926004B2 (en) | Capacitive sensor | |
JPH09174878A (en) | Detecting system | |
US4700754A (en) | Arrangement for controlling the level of an ink container | |
US6183054B1 (en) | Method and device for determining the quantities of consumable products contained in reservoirs grouped together next to one another and document printing device using this method | |
US6095629A (en) | Device for determining quantities of consumable products contained in reservoirs and a document printing device having several different reservoirs of pigmented products | |
US2541576A (en) | Apparatus for determining fluent level | |
US20080100681A1 (en) | Refilling a used ink cartridge | |
JP3032567B2 (en) | Ink detector for recording device | |
JP2931079B2 (en) | Ink detector for recording device | |
TW381170B (en) | Method and device for determining the quantity of product present in a reservoir, notably that of ink in an image forming device | |
JP2841662B2 (en) | Ink tank for inkjet recording device | |
JPH0639161B2 (en) | Inkjet recording device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): DE FR GB |
|
17P | Request for examination filed |
Effective date: 19961106 |
|
17Q | First examination report despatched |
Effective date: 19970506 |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: OLIVETTI LEXIKON S.P.A. |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 69424513 Country of ref document: DE Date of ref document: 20000621 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20131227 Year of fee payment: 20 Ref country code: DE Payment date: 20131230 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20131217 Year of fee payment: 20 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R071 Ref document number: 69424513 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: PE20 Expiry date: 20141212 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20141212 |